I have searched everything I can and can't find the answer to the problem I am having. I have a 1985 Rx-7 base model GS 12a, with an automatic transmission. I have recently replaced the front & rear brakes including the calipers and all. Heres the problem. I also replaced the front brake hoses on both sides that connect from the caliper to the brake line and they are leaking from the fitting on both sides. It leaks from where the brake line connects to the hose with that clip installed to hold the brake hose in place in the wheel well. I thought it might have been defective hoses so I bought another set from Advance Auto and tried them. Same problem, both hoses leak at the fitting. There is no washer that goes there and the brake lines from the master cylinder are fine. Both sets of lines fit perfectly with no installation problems, they just leak. I am totally baffled by this. 2 brand new sets of hoses that both leak?? A friend of mine told me that even though Advance Auto and other parts places show these hoses being the correct ones for the car that I needed to go to the Mazda dealership with the VIN # to get the correct brake hoses for the car. He said that the brake hose fitting has a specific design that seals against the flange on the brake line but you have to get the right one for the car. Does anyone know if that is the case? The Mazda dealership is closed so I can't call. I need help if anyone can please advise. Thank you.

 

The brake lines don't seal by the threads, the seal by the inner mating surfaces. Inspect those for any flaws, burs or corrosion. Compare the new lines to your old lines, the new ones may not have the correct profile.

 

there is supposed to be a small copper crush washer between line and caliper....

 

I think he is talking about the connection between the hard lines and the flex lines. This joint seals by the flange of the hard line compressing against a cone like flange on the inside of the flex line fitting. Check your flex lines for this.

The copper washer is to seal the joint between the flex line and the caliper. From the sounds of it, these joints aren't leaking.

 

I bet he stripped them threads.

 

could he have been given flex lines with the wrong thread pitch? also check the hard line end for splits.

 

Also look inside the end of the new lines and the old flax lines. Make sure the cone in the middle looks the same. Post pics of this if you can.

There are inverted flare and double inverted flare fittings. You may not have the correct ones.

-billy

 

Thanks for the replies, it's appreciated. The threads aren't stripped it simply doesn't seal. It is where the soft line connects to the hard line where it attaches to the side of the wheel well. You have the clip the holds the soft line in place and then the hard line screws into the soft line. That's where it's leaking at. I will be going to the Mazda dealership this week and see what they say. I would have went already but the storm and work kept me from going. I don't have a camera so I can post pictures of what I'm referring to. I'll post whatever the Mazda dealership advises. Thanks.

 

It always helps to check your new part against the old part that it is replacing.

Might be that the mating surfaces are not male-male, or female-female, That is cone inward and cone outward.

When they should be male-female.

 

Unfortunately in my stupidity I didn't check the old hoses for that. A lot of the rubber had come off the hoses so I just wanted to replace them, I didn't think about whether or not the fittings would be correct on replacement hoses. That's what I get for not checking. I know the hardline is cone inward. The replacement hoses were cone outward. I tried two different sets of brand new hoses and both leaked. Hopefully the Mazda dealership can help me figure it out. It's amazing, I replaced the front and rear brakes with all new parts, calipers, wheel cylinders etc. and the only problem is with the hoses. All the other parts fit perfect and are fine. Oh well. Thank you again for your responses.

 

Just look at the end of the hard lines. IIRC they have a "funnel" look to them where the linejust looks like it is flared out and the threaded fitting pushes against the perimeter of the funnel. If that is the case the flex line needs to have a "cone" shape inside the base of the female thread cup. The cone gets smashed up inside funnel and you have a seal.

If your hard line looks like it has a bubble on the end you need a tapered bottom inside the threaded female part(like a drill bit would make when you don't go all the way through the material).

That pretty much covers the fitting and seal surfaces you will find.

 

"Hopefully the Mazda dealership can help me figure it out."

You make a joke!